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Alan Stevens


Last seen: Today
740 total contributions since 2020

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Answered
Single bubble expansion equation
Try starting your bubble radius as 2*sigma/1.4, rather than 0.

alrededor de 13 horas ago | 0

Answered
Coupled rate ODEs with ode45
It can all be done in one script as follows. Because of the orders of magntude difference between the various concentrations th...

alrededor de 19 horas ago | 0

Answered
How can I call the highest order solution (e.g. x'') of an ode in another ode?
You can rearrange the equations as follows to get a consistent set: (you will need to use explicit multiplication where my eq...

alrededor de 21 horas ago | 0

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Answered
How can I make a loop that gives values in each iteration?
Why do you need a loop? There is just one zero between 2 and 8. Your values of w are not used in any meaningful way (they woul...

alrededor de 24 horas ago | 0

Answered
How to use ODE 45 to generate a SIR model
Like so: alpha=1.99; beta=1; gamma=1/7; S=0.99; I=0.01; R=0.1; %tstart=0; %tend=100; y=[S,I,R]; tspan=0:1:100; [t,sol...

1 día ago | 2

Answered
error in using the function fsolve to find steady state
Using the Optimization toolbox to solve these equations seems like using a sledgehammer to crack a nut! It is clear from the eq...

2 días ago | 0

Answered
I am trying to solve ODE having more than 1 dependent variable. but I am not able to solve it with dsolve function. please help me to find correct function to solve ODE.This is an mechanical engineering equation so it is bit complicated and lengthy
Here's a possible way using ode45. I've used arbitrary initial values for the three temperatures, so you will need to replace t...

2 días ago | 1

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Answered
MATLAB Newton Raphson Method with a function with array/matrix variables
You could do it like this f = @(x,g) g.*exp(x) - 1; df = @(x,g) g.*exp(x); g = [1 2 3 4 5]; for i= 1:numel(g) x0 = 0...

2 días ago | 1

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Answered
When i try to create function error "Unable to perform assignment because the left and right sides have a different number of elements." comes up
Try n=-25:25; x3=zeros(1,length(n)); x3(n>=2 & n<=22)=exp(j*(0.5)).^(2:22);

2 días ago | 0

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Answered
Explicit Eulers Method for time advancement
T(i)^(n+1) This will raise T(i) to the (n+1)th power! You need another loop for time (say j = 1:something), then you can refer...

2 días ago | 0

Answered
Hot to fit two curves under interdependent constraint ?
How about just using fminsearch x = linspace(1,100,100); % Measurement results: y1=[0.07469056,0.07378624,0.07288704,0.071992...

3 días ago | 0

Answered
Need assistance using bisection method to find equation roots in Matlab function.
Try this % input for function that we're finding the roots of f1 = @(x) ((-0.6)*x^2)+(2.4*x)+(5.5); xl = 5; % xl sets the i...

3 días ago | 0

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Answered
Errors in Newton Raphson Code
Again, more like this % f = 3*exp(x)-4*cos(x) % df/dx = 3*exp(x)+4*sin(x) i=1; x=0.1; err = 1; while err>10^-8 && i<100 ...

3 días ago | 0

Answered
Error in Newton-Raphson Method
Like this R=15/2; v=500; h=8; i=1; err = 1; while err>10^-8 && i<100 hold = h; fh = pi*h^2*(3*R - h)/3 - v; ...

3 días ago | 0

Answered
Plotting partial sums of series
Do you mean something like this? x = -pi:0.1:pi ; %initializing x S = zeros(20,numel(x)); figure xlim([1 20]) grid hold o...

3 días ago | 0

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Answered
Anonymous function surface plot
Are you looking for something like this? n = 2; x_opt = randi([-6,6],n,1); A = randi(n,n); T = A*A' + eye(n,n); h = -T*x_op...

4 días ago | 1

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Answered
Boucle for add the element behind
doc cumsum

4 días ago | 1

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Answered
Solving system of ODEs and Plotting
Something like this? timerange= [0 60]; [t, hvl] = ode45(@f, timerange, [0.9,0.1,0.2]); plot(t, hvl, 'LineWidth', 2),grid ...

5 días ago | 0

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Answered
Plot 3D of a function
Are you looking for something like this? x = linspace(0,pi); t = linspace(0,1); z = @(x,t) 10*exp(-4*t).*sin(2*x); [x1, t1] ...

6 días ago | 0

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Answered
Error using _*_. What am I doing wrong?
You need dots before the * and before the / , not after the t.

6 días ago | 1

Answered
Runge Kutta 4th Order Example
First, write your equation as two first order equations; xdot = v, say, and vdot = -9xdot - 0.1x^3 Then define two functions ...

6 días ago | 1

Answered
Find intersection point between a vertical line and another line.
You could insert a conditional: AlineX=[0 0]; AlineY=[0 400]; BLineX=[1180 570]; BLineY=[-289.5 250]; p1 = polyfit(Alin...

6 días ago | 1

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Answered
Solving second order inhomogeneous differential equations which are not a function of time
Break the ode into two first order ode's. e.g. dy/dx = v; dv/dx = f(x) - p*v - q*y; Look up the documentation on ode45 ...

7 días ago | 0

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Answered
Invalid expression. When calling a function or indexing a variable, use parentheses. Otherwise, check for mismatched delimiters
Your line v(n)= 4(-1)^(n-1)/(2(n-1)+1)+pi_estimate should be v(n)= 4*(-1)^(n-1)/(2*(n-1)+1)+pi_estimate Note: | ...

7 días ago | 0

Answered
How do I plotting Matlab functions, ode23, exact value functions side by side?
Like this format long r=5000; c=200*(10^(-6)); vs=10; tf=3; %%%%%%%%%%%%%%%%%%%%%%%%% %% 2 exact solution for charging an...

7 días ago | 1

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Answered
Need to plot a graph of -y(t) and x(t) on MATLAB
Here are the equations that you will need to include in your pend function. Now let's see you implement them!

7 días ago | 0

Answered
solving system of 2 equations with complex components
Here's a non-symbolic way to solve your equations ki0 = 200; kp0 = 10; k0 = [ki0, kp0]; k = fminsearch(@search,k0); ki =...

7 días ago | 0

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Answered
2 Line Styles for A Single Plot- How to Change Plotting Styles
Here's one possibility B = 0.75; C = 0.8; p =0.5; A = linspace((1-p)*B*(1-C),1.5); figure (2) [l1,l2]= bifurcation_lysogen...

7 días ago | 0

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Answered
Plotting the results of 2 ODE45 in the same figure
You need to check the placing of your parentheses in the forcing functions. Try tspan = 0:1800; y0 = [0;0]; [t,y] = ode45 (@...

7 días ago | 0

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